Lifting system with counterweight pulleys and cage aligned on the same axis of symmetry

ABSTRACT

The invention relates to a lifting system for the transport of persons and for the movement of goods, with a traction unit (G) for a cage or goods hoist (10) provided with relative guides (18, 20), vertically movable inside a vertical run space (12) of a building between areas with a given height difference and provided with a bottom, side walls, a roof and mobile cage doors, in particular an electric wire rope elevator, with traction unit inside said vertical run space of the type called MRL (Machine Room Less), comprising a load supporting frame (14) and relative snub pulleys (28, 30), a moving counterweight (16) with relative guides (22, 24) and a snub pulley of the counterweight (32). In said system, said pulleys of the counterweight (16), of the traction unit (G) and of the frame (14) supporting the load contained in said cage, are aligned on the same axis, allowing the space useful for the movement of the cage to be optimised and thus making it possible to install a traction unit with greater lifting capacity.

The present invention relates to a lifting system with counterweight andcage pulleys aligned on the same axis of symmetry.

More particularly, the present invention relates to a lifting system asdefined above, suitable for both the transport of persons and themovement of goods, comprising a cage or goods hoist, movable verticallyinside a run space of a building between zones having a certaindifference in height and provided with a bottom, side walls, a roof andmobile cage doors. Areas with a certain difference in height define thefloors of the building; the run space in which the cage or hoist movesvertically is provided with openings at the various floors; the cage, inparticular, has one or more entrances with manually or automaticallyopening cage doors while on the various floors of the building, at runspace openings there are also floor doors. The cage moves along rigidguides, the inclination to the horizontal of which is greater than 15degrees.

As is known, the movement of the cage is carried out by a motor unit,typically arranged at the upper end of the run space; hereinafter,reference will be made by way of example to electric wire ropeelevators, with traction units inside the vertical run space, called MRL(Machine Room Less), which define the state of the art closest to thesolution of the invention. Electric wire rope elevators arecharacterised by the fact that they are moved by a counterweight andinclude, as main components, a frame to support the load placed insidethe mobile cage, traction cables, deflection or snub pulleys and amovement unit associated with said cage, which also controls itslevelling at the floor. The most commonly used movement units are mainlyof two types, i.e. geared winches or gearless winches; in the lattercase, gearless winches are electrically actuated and have no mechanicaltransmission.

Reference will now be made only to lifts with gearless winches, whichrepresent the scope of operation to which the solution of the presentinvention refers.

The known solutions of this type have a significant drawback, due to thefact that the space useful for the movement of the cage is notoptimized. In fact, according to a known solution, the continuation ofthe axis of symmetry of the cage guides is external to the area whichthe counterweight pulleys look onto; this in the case of a conventionalcable system with a special machine room, located above the upper end ofthe run space. In particular, the intersection of the centre line of thecage guides with that of the counterweight pulleys takes place only ifsaid axes are extended with respect to the back of said guides. Thetraction unit supported by the support having one or more deflectionpulleys rests on the floor of the machinery room and is positioned onthe connection axis of the centres of symmetry of the respectivecounterweight and cage guides. Use inclination of the alignment withrespect to the centreline axes of the guides imposes a rotation of thecables, which causes further inconvenience related to the wear of thetraction means, imposing expensive replacement of the same; according tothis solution the pulling of the system is direct, without thepossibility of using snub pulleys to exploit the 2:1 suspension, whichwould allow a reduction of the power used by the traction unit.

In another case, the continuation of the axis of symmetry of the cageguides could be inside the area facing the counterweight guides, in thecase of a cable system equipped with traction units located inside theupper end of the run space and supported directly by the counterweightguides and the single cage guide. In this case, the axis of symmetry ofthe cage guides is perpendicular and internal to the axis facing thecounterweight guides, but this requires a 90° rotation of the tractioncables in the passage from the traction pulley to the mobilecounterweight deflection pulley. Consequently, this rotation of thetraction means causes wear and tear of the same and makes costlyreplacements necessary; moreover, this known solution limits the numberof cables that can be used.

In addition, the maximum permissible inclination of the cables withrespect to the traction pulley grooves must be lower than 4° accordingto the regulations; this limit imposes distances and dimensions that donot allow a reduction in height of the upper end of the run space. Forall these reasons an increase of the upper end of the run space ismandatory with relative costs.

WO 2004/106206 relates to a lift driven vertically by guide railsarranged diagonally. In particular, this solution relates to cage guidesthat are on separate axes, wherein the third guide serves only toprevent rotation and is not used to guide said cage. In the patent GB 2395 191 the elevator machine and the counterweight are suspended on thelifting cables by a deflection pulley; the cage guides are not howeverconsidered.

In EP 1 616 833 a lift with cage intended for persons and goods includesflat and parallel load bearing belts as a connection between said cageand a counterweight; the belts are aligned on parallel vertical planesand the main guides are arranged diagonally. JP 2002 173279 alsodiscloses the solution of making a lift in which the lateral guides arepositioned on the internal surfaces of the axis of the lift itself toreduce the dimensions, with the lateral pulleys of the cage arrangeddiagonally.

The purpose of the present invention is to overcome the aforesaiddrawbacks.

More particularly, the purpose of the present invention is to provide alifting system, for MRL lifts with traction units inside the run spacein which the arrangement of the cage guides and the counterweight allowsthe space useful for the movement of the cage to be optimised.

A further and consequent purpose of the invention is to provide alifting system as defined above in which the optimization of the spaceuseful for the movement of the cage makes it advantageously possible toinstall a traction unit with greater lifting capacity than theconventional solutions.

A no less important purpose of the invention to provide a lifting systemcapable of preventing the rotation of the traction cables, therebyreducing their wear.

A further purpose of the invention is to make available to users alifting system suitable to ensure a high level of resistance andreliability over time, in addition such as to be easily and economicallymade.

These and other purposes are achieved by the lifting system of thepresent invention according to the main claim.

The construction and functional characteristics of the lifting system ofthe present invention will be more clearly comprehensible from thedetailed description below in which reference is made to the appendeddrawings which show a preferred and non-limiting embodiment and wherein:

FIGS. 1, 2 and 3 show schematically in as many plan views theconfiguration of a cable lifting system of the known type, respectivelyprovided in the first case with the appropriate machinery space locatedabove the upper end of the run space and without, in the second case,such a special machinery space, but with the traction unit inside theupper end of the run space;

FIG. 4 schematically shows the plan configuration of a cable liftingsystem in accordance with the present invention, wherein the tractionunit is positioned inside the upper end of the run space;

FIG. 4A schematically shows the plan configuration of the same cablelifting system in accordance with the present invention to highlight theincrease obtainable as regards the extension of the surface of the cagefloor compared to conventional solutions;

FIG. 5 schematically shows a view analogous to the above, with the snubpulleys positioned according to the arrangement of the invention;

FIG. 6 schematically shows, from a perspective view, the counterweightconstraint kinematics to the respective guides according to theinvention;

FIG. 7 schematically shows a perspective view of the counterweightaccording to the invention, wherein the snub pulley is decentralizedwith respect to the axes of symmetry.

With reference to the aforesaid figures, the lifting system according tothe present invention comprises a traction unit (G) for a cage or goodshoist 10 that is moved in a run space 12, as shown in FIG. 2, on whichthe load support frame and the movement counterweight are indicated,respectively, as 14 and 16; in FIG. 1 a traditional winch is furtherschematically shown as A.

FIG. 3, on the other hand, schematically illustrates a known arrangementof the axis of symmetry of the cage guides 18 and 20, the continuationof which is inside the area which the counterweight guides, indicated as22 and 24, face onto in the case of a cable system having the tractionunit, supported directly by said guides of the counterweight and thesingle guide (18) of the cage inside the upper end of the run space. Inthis case, the axis of symmetry of the cage guides 18 and 20 isperpendicular and internal to the facing axis of the counterweightguides 22 and 24, thus imposing a 90° rotation of the traction cables(not illustrated) in the passage from the traction pulley (T1) (FIG. 2)to the movable 32 deflection pulley of the counterweight 16, with thedrawbacks stated above.

According to the invention, with particular reference to FIG. 4, thetraction pulley now indicated as T2 is aligned on the same axis ofsymmetry as both the counterweight 16 and the lifting kinematics or snubpulleys indicated as 28, 30, installed for the movement of the frame 14supporting the load. According to this configuration illustrated in FIG.4, the arrangement of the cage pulleys defined by the lifting kinematicsor snub pulleys 28, 30 optimizes the useful space for the movement ofthe load support, allowing an increase in the surface area of the floorof the cage 10 compared to that obtained with the solutions of the priorart; the area defining such an increase in the surface area of the floorof the cage 10 is shown as a dashed line 42 in FIG. 4A. Furthermore, thecage guide 18 in FIG. 3, interposed between the cage 10 and thecounterweight 16 in conventional solutions, is not seen in the solutionof the present invention, which allows said spaces to be optimized. Inthe lifting system of the present invention, the lifting kinematics orsnub pulleys 28, 30, 32 illustrated in FIGS. 4 and 5 have a reduceddiameter, equal to 120 mm compared to the usual 240 mm. The snub pulley32 is rotated by 90° with respect to traditional solutions, such as thatshown schematically in FIG. 3; this rotation allows the alignment of thetraction pulley T2 and the lifting kinematics or snub pulleys 28 and 30,32 on the same axis of symmetry, as can be seen in FIGS. 4 and 5.

It should be further considered that the decentralization of thecounterweight snub kinematics 32, as shown schematically in FIG. 5,limits the distance between the lifting kinematics defined by the snubpulleys 28, 30, installed for the movement of the support frame 14supporting the load, and the axis of symmetry of the cage guidesindicated as C in FIG. 5, reducing the stresses and resistant momentsgenerated during the suspension and movement of the load. An incision,indicated as 44 in FIG. 6, defines a channel on the roller surface ofthe restraint kinematisms 34 and allows the correct alignment of thecounterweight 16 during the movement of the frame relative to the axisof the guides 22 and 24 of said counterweight, preventing dangerousderailing. Said kinematics then make rotation possible thereby avoidingwedging of the counterweight 16 during its stroke, while the structuralstrength of the frame of said counterweight frame is guaranteed byappropriate constraints 36, shown schematically in FIG. 7, which connectthe vertices 38 and 40 of said counterweight 16.

As may be seen from the above, the advantages which the inventionachieves are significant.

The lifting system of the present invention allows a reduction of thedimensions of the mechanical component and, consequently, a significantincrease in the space useful for the movement of the cage advantageouslypossible.

Despite the invention having been described above with particularreference to one of its embodiments, given solely by way of anon-limiting example, numerous modifications and variants will appearevident to a person skilled in the art in the light of the abovedescription. The present invention therefore sets out to embrace all themodifications and variants which fall within the sphere and scope of thefollowing claims.

1. A lifting system for the transport of persons and for the movement ofgoods, with a traction unit (G) and traction pulley (T2) for a cage orgoods hoist (10) provided with relative guides (18, 20), verticallymovable inside a vertical run space (12) of a building between areaswith a given height difference and provided with a bottom, side walls, aroof and mobile cage doors, in particular an electric wire ropeelevator, with traction unit inside said vertical run space of the typecalled MRL (Machine Room Less), comprising a load supporting frame (14)and relative snub pulleys (28, 30), a moving counterweight (16) withrelative guides (22, 24) and a snub pulley of the counterweight (32),characterized in that said counterweight (16), traction (T2) and frame(14) pulleys supporting the load contained in said cage are aligned onthe same axis.
 2. The lifting system according to claim 1, characterizedin that the axis of symmetry of the cage guides (18, 20) is outside thearea which the guides (22, 24) of the counterweight (16) look onto. 3.The lifting system according to claim 1, characterized in that the axisof the pulley (32) of the counterweight (16) is decentralized relativeto the centreline axis which the relative guides (22, 24) look onto. 4.The lifting system according to claim 1, characterized in that thecounterweight (16) comprises constraints (34) made with kinematics fixedat the vertices (38, 40) of said counterweight.
 5. The lifting systemaccording to the preceding claims, characterized in that the arrangementof the snub kinematic mechanisms or snub pulleys (28, 30, 32) results inan increase in the movement spaces of the load support, with a greatersurface area (42) of the cage floor (10).
 6. The lifting systemaccording to claim 4, characterized in that it comprises an incision(44) that defines a channel on the surface of the restraints roller (34)and allows the correct alignment of the counterweight (16) during themovement of the frame relative to the axis of the guides (22, 24) ofsaid counterweight.
 7. The lifting system according to claim 5,characterized in that the lifting kinematism or the snub pulleys (28,30, 32) have a diameter of 120 mm.